On 02/13, Tero Kristo wrote: > On 24/01/17 00:17, Tony Lindgren wrote: > >Texas Instruments omap variant SoCs starting with omap4 have a clkctrl > >clock controller instance for each interconnect target module. The clkctrl > >controls functional and interface clocks for the module. > > > >The clkctrl clocks are currently handled by arch/arm/mach-omap2 hwmod code. > >With this binding and a related clock device driver we can start moving the > >clkctrl clock handling to live in drivers/clk/ti. > > > >Note that this binding allows keeping the clockdomain related parts out of > >drivers/clock. The CLKCTCTRL and DYNAMICDEP registers can be handled by > >a separate driver in drivers/soc/ti and genpd. If the clockdomain driver > >needs to know it's clocks, we can just set the the clkctrl device > >instances to be children of the related clockdomain device. > > > >Each clkctrl clock can have multiple optional gate clocks, and multiple > >optional mux clocks. To represent this in device tree, it seems that > >it is best done using four clock cells #clock-cells = <2> property. > > > >The reasons for using #clock-cells = <2> are: > > > >1. We need to specify the clkctrl offset from the instance base. Otherwise > > we end up with a large number of device tree nodes that need to be > > patched when new clocks are discovered in a clkctrl clock with minor > > hardware revision changes for example > > > >2. On omap5 CM_L3INIT_USB_HOST_HS_CLKCTRL has ten OPTFCLKEN bits. So we > > need to use a separate cell for optional gate clocks to avoid address > > space conflicts > > > >There is probably no need to list input clocks for each clkctrl clock > >instance in the binding. If we want to add them, the standard clocks > >binding can be used for that. > > > >For hardware reference, see omap4430 TRM "Table 3-1312. L4PER_CM2 Registers > >Mapping Summary" for example. It shows one instance of a clkctrl clock > >controller with multiple clkctrl registers. > > > >Cc: Paul Walmsley <paul@xxxxxxxxx> > >Acked-by: Rob Herring <robh@xxxxxxxxxx> > >Signed-off-by: Tony Lindgren <tony@xxxxxxxxxxx> > > This binding works for me, so: > > Acked-by: Tero Kristo <t-kristo@xxxxxx> > This wasn't in the TI clk PR. Shall I merge this to clk-next? -- Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux Foundation Collaborative Project -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
